Mnemonic Role Research Articles

A role for maternal physiological state in preserving auditory cortical plasticity for salient infant calls

A growing interest in sensory system plasticity in the natural context of motherhood has created the need to investigate how intrinsic physiological state (e.g., hormonal, motivational, etc.) interacts with sensory experience to drive adaptive cortical plasticity for behaviorally relevant stimuli. Using a maternal mouse model of auditory cortical inhibitory plasticity for ultrasonic pup calls, we examined the role of pup care versus maternal physiological state in the long-term retention of this plasticity. Very recent experience caring for pups by Early Cocarers, which are virgins, produced stronger call-evoked lateral-band inhibition in auditory cortex. However, this plasticity was absent when measured post-weaning in Cocarers, even though it was present at the same time point in Mothers, whose pup experience occurred under a maternal physiological state. A two-alternative choice phonotaxis task revealed that the same animal groups (Early Cocarers and Mothers) demonstrating stronger lateral-band inhibition also preferred pup calls over a neutral sound, a correlation consistent with the hypothesis that this inhibitory mechanism may play a mnemonic role and is engaged to process sounds that are particularly salient. Our electrophysiological data hint at a possible mechanism through which the maternal physiological state may act to preserve the cortical plasticity: selectively suppressing detrimental spontaneous activity in neurons that are responsive to calls, an effect observed only in Mothers. Taken together, the maternal physiological state during the care of pups may help maintain the memory trace of behaviorally salient infant cues within core auditory cortex, potentially ensuring a more rapid induction of future maternal behavior.

Fimbria–fornix and entorhinal cortex differential contribution to contextual and cued fear conditioning consolidation in rats

The Fimbria–Fornix (FF) and Entorhinal Cortex (EC) are the primary interfaces between the hippocampus and, respectively, subcortical structures and cortical areas. Their mnemonic role has been repeatedly proposed. In order to investigate their role in fear conditioning, FF and EC were subjected to bilateral fully reversible tetrodotoxin (TTX) inactivation during consolidation in adult male Wistar rats that had undergone training for fear conditioning to an acoustic stimulus (CS) and context. TTX was stereotaxically injected into animals of different groups at increasing post-acquisition delays. Memory was assessed as conditioned freezing duration measured during retention testing, performed 72 and 96h after TTX administration in a counterbalanced manner. The results showed that FF inactivation, performed immediately after conditioning, did not disrupt consolidation of either contextual or auditory fear memory. On the contrary, EC inactivation performed at the same time was followed by both contextual and CS fear response retention impairment. EC inactivation performed 1.5h post-acquisition impaired only contextual fear response retention. EC inactivation performed 24h after acquisition training had no effect on the consolidation process. The present findings show a clearly different role of FF and EC in fear conditioning consolidation in the rat. The results are discussed in relation to their known connections with the hippocampus.

Musical mnemonics in health science: A first look

Song, with its memory enhancement potential and ability to engage, has been employed as a learning tool in some academic settings. Of the countless learning environments, health science may seem the most atypical setting for the musical mnemonic, and yet it may be the most suitable for its application. With medicine's robust history of student-made mnemonics, it only seems natural that learners and instructors alike have begun to experiment with song meant to educate and entertain, primarily imparting them through popular media-sharing sites. This initial assessment of song in health science is meant to highlight notions of efficacy, audience, and use through an informal survey of 10 user-made YouTube musical mnemonics. Two of these mnemonics were co-created by the author, while the remaining eight were identified via select search terms and significant viewer numbers. Resulting YouTube data infers that instructors play a major role in the use of musical mnemonics in health science education. User comments indicate that some students have found value in mnemonic songs, helping them recall information during assessments. More robust research methods, like Q-method, meta-analysis, and opinion mining, can further confirm the value and role of musical mnemonics as they pertain to medicine and healthcare.

Adaptation to Conflict via Context-Driven Anticipatory Signals in the Dorsomedial Prefrontal Cortex

Behavioral interference elicited by competing response tendencies adapts to contextual changes. Recent nonhuman primate research suggests a key mnemonic role of distinct prefrontal cells in supporting such context-driven behavioral adjustments by maintaining conflict information across trials, but corresponding prefrontal functions have yet to be probed in humans. Using event-related functional magnetic resonance imaging, we investigated the human neural substrates of contextual adaptations to conflict. We found that a neural system comprising the rostral dorsomedial prefrontal cortex and portions of the dorsolateral prefrontal cortex specifically encodes the history of previously experienced conflict and influences subsequent adaptation to conflict on a trial-by-trial basis. This neural system became active in anticipation of stimulus onsets during preparatory periods and interacted with a second neural system engaged during the processing of conflict. Our findings suggest that a dynamic interaction between a system that represents conflict history and a system that resolves conflict underlies the contextual adaptation to conflict.

Metabotropic Induction of Persistent Activity in Layers II/III of Anterior Cingulate Cortex

The anterior cingulate cortex (ACC), a limbic region associated with pain-related working memory and memory acquisition, receives a dense cholinergic innervation. To further understand the role of acetylcholine in ACC, we characterized the firing properties of pyramidal neurons following muscarinic receptor activation. Using whole-cell patch clamp recordings in acute brain slices, we report long-lasting nonsynaptic plateau potentials and persistent firing induced by carbachol (CCh) in pyramidal neurons in layers II/III of rat ACC. CCh responses were abolished by the muscarinic receptor antagonist atropine or by inhibitors of G proteins and phospholipase C. Inhibiting L-type calcium channels with nifedipine, removing extracellular calcium or chelating intracellular calcium with BAPTA also abolished plateau potentials and persistent firing. Blockade of nonselective cation channels with flufenamic acid, 2-aminoethyl diphenylborinate or SKF-96365 suppressed CCh responses and voltage-clamp recordings of CCh-sensitive currents revealed a transient receptor potential canonical-like cationic conductance. The group I metabotropic glutamate receptor (mGluR) agonist (S)-3,5-dihydroxyphenylglycine hydrate induced plateau potentials and persistent firing that were mediated by mGluR5. Our data demonstrate that receptor-operated channels drive calcium-dependent plateau potentials and persistent firing in layers II/III of ACC. Therefore, acetylcholine- and glutamate-evoked persistent activity in ACC may play a mnemonic role by allowing transient storage of information during pain processing.

Die Latenz der Fotografie. Zur Medientheorie des Erinnerns in Marcel Beyers Spione

With the advent of the iconic turn in the mid-1990s, studies on cultural memory gained a new dimension by focussing on the mnemonic role of images. In this context, photography and its relation to textual media like literature became a preeminent research object. The present essay analyses a text that develops, although itself literary, an intricate theoretical reflection on the matter: Marcel Beyer's novel Spione , written in 2000. According to Spione , photos may not be considered as windows into former times, but as surfaces hiding a multi-faceted past. Photography thus appears as a medium of deception and latency rather than of elucidation. Consequently, the recollection of the past resembles the decipherment of delusive messages and the disclosure of mysteries—typical activities of spies who are prominently quoted in the novel's title.

Social Remembering and Organizational Memory

Organizational Memory Studies (OMS) is limited by its managerialist, presentist preoccupation with the utility of memory for knowledge management. The dominant model of memory in OMS is that of a storage bin. But this model has been rejected by psychologists because it overlooks the distinctly human subjective experience of remembering, i.e. episodic memory. OMS also fails to take account of the specific social and historical contexts of organizational memory. The methodological individualism that is prevalent in OMS makes it difficult to engage with the rapidly expanding sociological and historical literature in social memory studies, where a more social constructionist approach to ‘collective memory’ is generally favoured. However, for its part social memory studies derived from Maurice Halbwachs neglects organizations, focusing primarily on the nation as a mnemonic community. From a critical perspective organizations can be seen as appropriating society’s memory through corporate sites of memory such as historical visitor attractions and corporate museums. There is scope for a sociological and historical reorientation within OMS, drawing on social memory studies and focusing on corporate sites of memory, such as The Henry Ford museum complex, as well as the mnemonic role of founders and beginnings in organizations. Taking a social constructionist, collectivist approach to social remembering in organizations allows connections to be made between memory and other research programmes, such as organizational culture studies.

Prime Time Commemoration: An Analysis of Television Broadcasts on Israel's Memorial Day for the Holocaust and the Heroism

This study explores the ways in which commercial media perceive and manifest their public mnemonic role. It does so via an exploration of the “memory menu”—the contents and flow of programming—offered by Channel 2, Israel's leading commercial television channel, on the eve of the country's Memorial Day for the Holocaust and the Heroism (MDHH), in which the airing of commercials is banned. In order to do so, the study incorporates a multilevel analysis that probes the structure of entire broadcasting evenings as well as the narrative building blocks that constitute each item. The study investigates the ways in which commercial media outlets operate in the context of “commercial vacuums” as they substitute material capital with symbolic capital. This process is illuminated through Channel 2's inability to work MDHH into its extremely successful routine broadcasting formulas. The channel's MDHH broadcasts construct a commemorative narrative that is insulated from day-to-day Israeli public Holocaust memory discourse; hence they operate as a significant site of Israeli postmemory work. Furthermore, such a narrative not only commemorates the memory of the Holocaust itself but also the ways in which Israeli culture used to narrate the memory of the Holocaust in the past.

Taiwan’s Mythological Theme Parks: Mnemonic Guardians and Uncanny Imaginaries

Cornell University
 
 This paper analyzes the mnemonic roles of mythological theme parks in contemporary Taiwan. I investigate two popular theme parks, Madou’s “Prefecture that Represents Heaven” (代天府) and its single Taiwanese precedent, the “Palace of Southern Heaven” (南天宮) in Zhanghua. I term these sites “mythological theme parks” because they differ significantly in form and function from other popular religious temples throughout Taiwan and China. Though both theme park and temple are loci of social production and reproduction, the nature of interaction at mythological theme parks resembles in many ways that which occurs at the imaginary realms manufactured by secular theme parks. These mythological theme parks feature moral imaginaries displayed in sculptural and animatronic depictions of the afterlife and acts of filial piety. My study addresses both textual sources and ethnographic data, collected while conducting fieldwork during the summers of 2004 and 2005, to evaluate how these mythological theme parks culturally convey the past into the present.

Effects of cholinergic deafferentation of the rhinal cortex on visual recognition memory in monkeys

Excitotoxic lesion studies have confirmed that the rhinal cortex is essential for visual recognition ability in monkeys. To evaluate the mnemonic role of cholinergic inputs to this cortical region, we compared the visual recognition performance of monkeys given rhinal cortex infusions of a selective cholinergic immunotoxin, ME20.4-SAP, with the performance of monkeys given control infusions into this same tissue. The immunotoxin, which leads to selective cholinergic deafferentation of the infused cortex, yielded recognition deficits of the same magnitude as those produced by excitotoxic lesions of this region, providing the most direct demonstration to date that cholinergic activation of the rhinal cortex is essential for storing the representations of new visual stimuli and thereby enabling their later recognition.

Changing Times in the Cultural Discourse of Late Medieval England

The author reassesses critical assumptions concerning ways to read time perceptions in the Middle Ages. A comprehensive synthesis of existing scholarship is offered as a means to scrutinize the multiple methods used by modern commentators and as a means to demonstrate the complexity and interconnectivity of cultural discourse in the medieval period. An integration of specialist approaches results in an essay with a wide coverage of primary sources. The focus on English examples— with close readings of how literary texts, religious writings, church records, legal documents, chronicles, letters, the computus genre, and the role of mnemonics— reveals the multiplicity of ways by which collective and individual attitudes towards time are instilled, communicated, explored, developed, confused, and at times subverted, in cultural discourse. This reading of timepieces as cultural narratives offers a new dimension in the study of medieval expressions of time. The essay also indicates possible directions for future study in this area.

Plasticity of the Hippocampal Place Cell Representation

The role of the hippocampus in the representation of 'place' has been attributed to the place cells, whose spatially localised firing suggests their participation in forming a cognitive map of the environment. That this map is necessary for spatial memory formation is indicated by the propensity of almost all navigational tasks to be disrupted by hippocampal damage. The hippocampus has also long been implicated in the formation of episodic memories, and the unusually plastic nature of hippocampal synapses testifies to its probable mnemonic role. Arguably, the place cell representation should, if it is to support spatial learning, be modifiable according to known principles of synaptic reorganization. The present article reviews evidence that the place cell representation is indeed plastic, and that its plasticity depends on the same neurobiological mechanisms known to underlie experimentally induced synaptic plasticity. Inferences are drawn regarding the architecture of the spatial representation and the principles by which it is modified. Spatial learning is promising to be the first kind of memory which is completely understood at all levels, from molecular through circuitry to behaviour and beyond.

Memory retrieval after contextual fear conditioning induces c-Fos and JunB expression in CA1 hippocampus.

Using specific polyclonal antisera against c-Fos, JunB, c-Jun and JunD, we tried to identify the candidate transcription factors of the immediate early gene family which may contribute to the molecular processes during contextual memory reconsolidation. For that purpose we analyzed the expression of these proteins in the hippocampus after contextual memory retrieval in a mouse model of fear conditioning. A single exposure to a foot shock of 0.8 mA was sufficient to induce robust contextual fear conditioning in C57BI/6N mice. In these mice context dependent memory retrieval evoked a marked induction of c-Fos and JunB, but not of c-Jun and JunD, in pyramidal CA1 neurons of the dorsal hippocampus. In contrast, mice exposed and re-exposed only to the context, without foot shock, did not show behavioral signs of contextual fear conditioning and exhibited significantly less expression of c-Fos and JunB in CA1 neurons. Mice which received a foot shock but were not re-exposed to the context revealed no immediate early gene induction. These results demonstrate that contextual memory retrieval is associated with de novo synthesis of specific members of the Fos/Jun transcription factor family. Therefore we suggest that these genes may contribute to plasticity and reconsolidation accompanying the retrieval process. The specific activation of CA1 neurons during the retrieval of contextual fear associations supports the postulated concept of a mnemonic role of this hippocampal subsector during the retrieval of contextual informations.

Age differences in memory for radio advertisements: the role of mnemonics

This study examines age differences in memory for radio advertisements. Younger and older adults listened to a bogus radio program. Half of each age category listened to a version of the program embedded with two ads utilizing a simple rhyming mnemonic device. The other half of each age category listened to the same program, but with ads without any rhyming mnemonics. Various measures of recall and recognition of the target ads were taken both immediately after exposure and after a 7-day delay. While no age differences in memory emerged, mnemonic versions of the ads resulted in better scores for overall unaided memory, prompted brand recall, and overall memory for both age groups. There were no differences in memory scores over the 7-day delay, nor were there any interaction effects.

Hippocampus and contextual fear conditioning: recent controversies and advances.

Dorsal hippocampal (DH) lesions produce a severe deficit in recently, but not remotely, acquired contextual fear without impairing memory of discrete training stimuli, i.e., DH lesions produce an anterograde and time-limited retrograde amnesia specific to contextual memory. These data are consistent with the standard model which posits temporary involvement of the hippocampus in recent memory maintenance. However, three recent controversies apparently weaken the case for a selective mnemonic role for the hippocampus in contextual fear. First, although retrograde amnesia (from posttraining lesions) is severe, anterograde amnesia (from pretraining lesions) may be mild or nonexistent. Second, a performance, rather than mnemonic, account of contextual freezing deficits in hippocampal-lesioned animals has been offered. Third, damage to the entire hippocampus, including the ventral hippocampus, can produce a dramatic and temporally stable disruption of context and tone fear. These data are reviewed and explanations are offered as to why they do not necessarily challenge the standard model of hippocampal memory function in contextual fear. Finally, a more complete description of the hippocampus' proposed role in contextual fear is offered, along with new data supporting this view. In summary, the data support a specific mnemonic role for the DH in the acquisition and consolidation of contextual representations.

The Role of the Fusiform Gyrus in Successful Encoding of Face Stimuli

PET was used to measure regional cerebral blood flow (rCBF) while memorizing pictures of unfamiliar human faces presented one at a time (FaceMemory). Other conditions included: (1) FaceRepeat—memorization of four individual faces presented repeatedly; (2) FaceWatching—viewing passively single faces without overt memory demands; and (3) Scrambled—counting dots superimposed on pictures of scrambled faces. After each FaceMemory condition and after the final FaceWatching condition scan, recall was tested by measuring face recognition. Contrasting FaceMemory and Scrambled conditions revealed several temporal activations: right midfusiform and bilateral anterior fusiform gyri. Contrasting FaceWatching and Scrambled conditions showed bilateral activation in the temporal poles and in the anterior fusiform gyri. No hippocampal activation arose from any contrast. Region of interest analyses on the above areas showed correlations with performance: (1) only rCBF in the right midfusiform correlated positively with encoding during the FaceMemory and FaceWatching conditions; (2) in the right temporal polar cortex rCBF decreased during FaceMemory and correlated positively with performance, whereas rCBF increased during FaceWatching and correlated negatively with incidental performance; and (3) activity in the anterior fusiform gyri remained constant across the conditions of FaceMemory, FaceRepeat, FaceWatching, and Scrambled and was uncorrelated with performance. These data suggest an expanded mnemonic role for the right midfusiform in depth of processing/encoding of face information, temporal polar cortex in face perception and recognition, and anterior fusiform activity in featural visual feature processing.

Effects of combined medial septal area, fimbria–fornix and entorhinal cortex tetrodotoxin inactivations on passive avoidance response consolidation in the rat

On the basis of previous experimental evidence, it has been concluded that the entorhinal cortex (EC), the fimbria–fornix (FF) complex and medial septal area (MSA) do not take part in the consolidation phase of passive avoidance response (PAR) memorization. On the other hand, a mnemonic role during consolidation of at least two of these structures has been argued, based on several considerations. In order to ascertain whether the EC and FF are still involved in PAR memorization during consolidation, the coupled fully reversible functional tetrodotoxin (TTX) inactivation of MSA, FF and EC was performed in rats having undergone a PAR training. In Experiment 1 MSA, FF and EC were inactivated pair-wise (FF and EC always bilaterally). Permanently cannulated animals were injected stereotaxically with TTX (5 ng in 0.5 μl saline) or saline (0.5 μl) immediately following PAR acquisition. It was shown that combined FF–EC inactivation induced PAR retention impairment, whereas FF–MSA and EC–MSA inactivation was not followed by amnesic effects. Having obtained a positive result, in Experiment 2 the combined FF–EC inactivation was performed at different post-acquisition delays (0.25 h, 1.5 h, 6 h), so as to assess the duration of their involvement in PAR consolidation. It was shown that only the coupled inactivation performed at the shortest post-acquisition delay was followed by amnesic effects. Thus EC and FF play a definite role during early consolidation. The results are discussed in relation to EC, FF, MSA, and hippocampal involvement in PAR memorization, as reported in previous studies, and to their connectivity.

Differential Effects of Dorsal and Ventral Hippocampal Lesions

Several studies have demonstrated that dorsal, but not ventral, hippocampus is critical for spatial memory. The mnemonic role of the ventral hippocampus remains unclear. The existence of relatively direct connections between hypothalamic nuclei and ventral hippocampus suggests that the ventral hippocampus may be involved in acquisition of information regarding internal cues (e.g., hunger). Male Long-Evans rats received ibotenic acid-induced lesions of either dorsal or ventral hippocampus or underwent sham surgeries. After a 3 week recovery, subjects were tested on delayed alternation in a T-maze and on a task in which food-deprivation state was used as a contextual cue (Davidson and Jarrard, 1993). Rats with dorsal, but not ventral, lesions were impaired in delayed alternation, consistent with previous findings, but both groups were impaired in the learning of the internal state-shock association task.

Amygdala Modulation of Multiple Memory Systems: Hippocampus and Caudate-Putamen

A series of five experiments examined the differential mnemonic roles of the hippocampus and caudate-putamen and the modulatory influence of the amygdala on hippocampal and caudate-putamen memory processes. Findings indicate that (a) posttraining intrahippocampal injections of amphetamine selectively enhance memory in a hidden platform water maze task, (b) posttraining intracaudate injections of amphetamine selectively enhance memory in a visible platform water maze task, (c) posttraining intra-amygdala injections of amphetamine enhance memory in both water maze tasks, (d) preretention intrahippocampal lidocaine injections block expression of the memory enhancing effects of posttraining intrahippocampal amphetamine injections in the hidden platform task, (e) preretention intracaudate lidocaine injections block expression of the memory enhancing effects of posttraining intracaudate amphetamine injections in the visible platform task, (f) preretention intra-amygdala lidocaine injections do not block the memory enhancing effect of posttraining intra-amygdala amphetamine injections on either task, (g) in the hidden platform task, posttraining intrahippocampal, but not intracaudate, lidocaine injections block the memory enhancing effects of posttraining intra-amygdala amphetamine, (h) in the visible platform task, posttraining intracaudate, but not intrahippocampal, lidocaine injections block the memory enhancing effects of posttraining intra-amygdala amphetamine. The findings indicate a double dissociation between the roles of the hippocampus and caudate-putamen in memory and suggest that the amygdala exerts a modulatory influence on both the hippocampal and caudate-putamen memory systems.

Role of dorsal hippocampus in acquisition, consolidation and retrieval of rat's passive avoidance response: a tetrodotoxin functional inactivation study

By means of local administration of tetrodotoxin (TTX) fully reversible functional inactivation of rat's dorsal hippocampus (DH) was obtained in order to define the role of this structure in the memorization of a conditioned passive avoidance response (PAR). In Experiment 1, on permanently cannulated animals, TTX (10 ng in 1.0 μ1 saline) or saline (1.0 μ1) was injected uni- or bilaterally in the DH, respectively 1 h before PAR acquisition, immediately after PAR acquisition, and 1 h before PAR retrieval, always performed 48 h after the acquisition trial. It was shown that both pre-acquisition and pre-retrieval DH uni- or bilateral blockades were followed by significant PAR retention impairment, while in post-acquisition only the bilateral blockade determined PAR retention impairment. In Experiment 2, on three different groups of rats, TTX (10 ng in 1 μ1 saline) was bilaterally administered, under general ketamine anesthesia (100 mg/kg), into the DH at different post-acquisition delays (0.25, 1.5, 6 h). Retrieval testing, 48 h after treatment, showed that post-acquisition bilateral DH blockade caused PAR impairment only when performed 0.25 or 1.5 h after acquisition. The results indicate a well defined mnemonic role of DH during the acquisition, consolidation and retrieval of PAR engram. The experimental evidence is discussed in relation to other reports and to DH connectivity with the medial septal area and the amygdala.